Our objective is to refine a hamster model of lung cancer. We seek that: (a) the primary occurs at a localized, pre-selected site, (b) the histologic behavior resembles human epidermoid cancer, (c) the evolution permits serial study of normal-to-neoplastic transitions in a predictable pattern. Young adult hamsters will receive sustained release implants (SRI) of varying doses of either Benzo(a)pyrene, Dimethylbenzanthracene, or Methylcholanthrene. The implants will initially be endobronchial. Later groups will have intraparenchymal implants. Hamsters will be sacrificed at intervals and the SRI will be assayed for residual carcinogen content. Bronchial washings will be subjected to cytologic and cytogenetic study, and correlation with histologic findings will be made. We shall separate the polyploid cells with a Facs IV cell sorter. Separated cells will be grown in tissue culture. Pooled blood samples will undergo hormone assay. Tissue and blood specimens will be assayed for ACTH and beta-lipoprotein as hormonal markers. From these studies we will define the pathogenesis of focal carcinogenesis in conjunction with its cytogenetic and hormonal correlates. Carcinogen release kinetics and dose-response determinations will be made. We shall determine the association between polyploidy and lung cancer and atypia.